1. Field of the Invention
This invention belongs to the field of biotechnology; namely, it describes a process to generate monoclonal antibodies using recombinant chimeric virus-like particles with inserted foreign protein fragments as immunogens. This process can be applied in hybridoma technology to generate new monoclonal antibodies against desired epitopes
2. Background to the Invention
To generate new monoclonal antibodies (MAbs) against any antigen, well-known and previously described methods include immunization with:                recombinant proteins;        synthetic antigens;        native proteins isolated from cells, tissues, etc.,        cell lysates (homogenates);        eukaryotic cells; or        viruses, bacteria.        
To generate monoclonal antibodies by hybridoma technology, strong immunogens are needed which are capable of activating both B and T cells and eliciting development of IgG antibodies. The immunogens are substances that induce an immune response. It is well documented that strong immunogens are proteins of high molecular weight. Peptides of low molecular weight (up to 50 amino acid long) are typically non-immunogenic. In order to generate monoclonal antibodies against peptides, they should be coupled to a carrier protein.
Different carrier proteins used in hybridoma technology are described: bovine serum albumin (BSA), keyhole limpet hemocyanin (KLH), tuberculin-related purified protein derivatives (PPD) and others [Bhatnagar P K, Papas E, Blum H E, et al., Acad Sci USA. 1982 July; 79(14):4400-4; Bashir I, Sikora K, Foster C S. Virchows Arch. 1998 March; 432(3):279-87].
Different methods of peptide coupling to the carrier protein are known. The peptide can be coupled to the carrier protein using different chemical reagents. For example, coupling using glutaraldehyde, carbodiimide and other chemical agents is well-known [Huhle G, Harenberg J, Malsch R, Heene D L. Semin Thromb Hemost. 1994; 20(2):193-204.] Photochemical coupling can be also used [Jurzak M, Boer R, Fritzsch G, Kojro E, Fahrenholz F. Eur J Biochem. 1990 May 31; 190(1):45-52.].
An alternative method is generation of synthetic peptides consisting of B and T cell epitopes [Fitzmaurice C J, Brown L E, McInerney T L, Jackson D C. Vaccine. 1996 April; 14(6):553-60].
The disadvantage of all these methods is that the peptide (or epitope) might be “hidden” inside the carrier protein and therefore might be not accessible to the cells of the immune system, namely, B cells that produce antibodies and are needed to generate hybridomas.
Another disadvantage of all these methods is that it is difficult to generate hybridomas producing antibodies against the peptide but not the carrier protein. As the carrier protein is much larger than the coupled peptide, the carrier contains more B cell epitopes and stimulates B cells more efficiently than the peptide. Therefore, even in the case if the peptide is accessible to B cells, usually the yield of hybridomas producing antibodies against the carrier protein is significantly higher than those producing antibodies against the peptide.
As such, there is a need for new more efficient method of producing monoclonal antibodies that overcomes the problems associated with methods of the prior art. In particular, there is a need for a method that allows the production of monoclonal antibodies against short peptides and non-immunogenic protein sequences for instance.